-.  ->  ;  / 


->    T 


r.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU   OF   ENTOMOLOGY-CIRCULAR   No.  155. 

L.  O.  HOWARD.   Fnlomologisl  tnd  Chirf  of  Bureau. 


INSECTS  INJURIOUS  TO  MUSHROOMS. 


BY 


C.  II.  POPEXOE, 
Entomological  Attiita  nt. 


WASHINGTON  :  GOVERNMENT  PRINTING  OFFICE  :  1t12 


BUREAU  OF  EXTOUOLOGY. 

L.  O.  Howard,  Entomologist  and  Chief  of  Bureau. 

C.  L.  Marlatt,  Entomologist  and  Acting  Chief  in  Absence  of  Chief. 

R.  S.  Clifton,  Executive  Assistant. 

W.  F.  Tastet,  Chief  Clerk. 

F.  H.  Chittenden,  in  <  harge  of  truck  crop  and  stored  product  insect  investigations. 

A.  D.  Hopkins,  in  charge  of  forest  insect  investigations. 

W.  D.  Hunter,  in  charge  of  southern  field  crop  insect  investigations. 

F.  M.  Webster,  in  charge  of  cereal  and  forage  insect  incest igat ions. 

A.  L.  Quaintance,  in  charge  of  deciduous  fruit  insect  investigations. 

E.  F.  Phillips,  in  charge  of  bee  culture. 

I).  M.  Rogers,  in  charge  of  preventing  spread  of  moths,  field  work. 

Bulla  I'.  Currie,  in  charge  of  editorial  work. 

Mabel  Colcord,  in  charge  of  library. 

Truck   Crop  and   Stored   Product   Insect   Investigations. 
F.   II.  Chittenden,  in  charge. 

II.  M.  Russell,  C.  II.  Fopenoe,  William  B.  Parker.  II.  O.  Marsh,  M.  M.  High, 

Fred  A.  Johnston,  John  E.  Gkae.  entomological  assistants. 
I.  J.  Condit.  collaborator  in   California. 
W.  X.  Obd,  collaborator  in   On  gnu. 
Thomas  II.  Jones,  collaborator  in  Porto  Rico. 
Marion  T.  Van  Horn,  Pauline  M.  Johnson,  Anita  M.  Ballinger,  preparators. 


Circular  No.  155. 


L91Z 


United  States  Department  of  Agriculture, 

BUREAU    OP    ENTOMOLOGY. 
L.    O.    HOWARD,    EntomoloRist    .in.l    Chief   of    Bureau. 


INSECTS   IN.M  IMOI  s  TO   MUSHROOMS. 

By  C.  ll    l'l'ii  hoi  . 
Entomological    I  ssistant. 

Cultivated  mushrooms,  especially  during  warm  weather,  are  at- 
tacked by  several  species  of  insect  pests  which  frequently  destroy 
an  entire  crop,  or  so  curtail  tin-  production  as  to  make  the  industry 
unprofitable.  Although  this  injury  is  al 
times  serious,  little  interesl  has  been  taken 
by  entomologists  in  the  matter  of  it-  i 
trol,  so  that  there  is  practically  n<>  available 
economic  literature  on  the  subject.  This 
circular  is  of  a  preliminary  nature,  as  the 
investigation  of  all  insects  injurious  to 
mushrooms  may  not  be  completed  for  some 
time. 

.'   insects  which   usually  attack  culti- 
vated mushrooms,  and  those  of  which  com- 
plaints are  most   frequently  made,  ma\ 
divided  roughly  into  four  classes,  namely, 

mushroom  maggots,  mites,  springtails,  and     '       '  ihroom  fly.  ApM- 

i  .1.1  '" ' 

sowbugs.     Ol    these  the   maggots   are   the        M 

mosl  generally  injurious,  the  mites  follow 

in  order  of  importance,  owing  to   the  difficulty   with   which   their 

eradication  is  accomplished,  and  then  come  springtails  and  sowbugs 

in  the  order  named. 

MUSHROOM  MAGGOTS. 
Bra  militia  ta  Fell  el  bL) 

The  injurious  forms  commonly  known  as  "mushroom  maggots"  are 
small  whitish  or  yellowish-white  maggots  usually  having  black  head-. 

fir.  156— 12  1 


2  INSECTS   INJURIOUS   TO   MUSHROOMS. 

They  are  the  young  of  certain  small  flies  or  "gnats,*'  two-winged 
and  mostly  black  in  color,  of  several  species  belonging  to  the  fami- 
lies Mycetopbilidae  and  Phoridse,  and  to  the  genera  Sciara  and 
Aphiochaeta.  Of  these  the  species  belonging  to  the  genus  Sciara  are 
by  far  the  most  common  and  injurious  of  mushroom  pests.  They  are 
minute  in  size,  measuring  about  three  thirty-seconds  of  an  inch  in 
length  and  about  one-eighth  inch  in  spread  of  wings.  They  are 
smoky  or  dusty  black  in  color.  The  species  attracting  most  atten- 
tion as  pests  are  Sciara  multiseta  Felt  and  Sciara  agraria  Felt.  Both 
species  are,  like  the  other  mushroom  gnats,  rapid  and  prolific  breed- 
ers, especially  during  warm  weather,  frequently  occurring  in  mush- 
room houses  so  abundantly  as  to  darken  the  windows.  They  may 
be  readily  confused,  however,  with  gnats  of  the  same  genus  which 
breed  in  manure  or  in  greenhouse  soil,  and  determinations  should 
always  be  made  by  a  specialist. 

Another  common  species,  Aphiochceta  albidihalteris  Felt  (fig.  1), 
superficially  resembles  the  preceding,  and  has  much  the  same  habits, 
but  as  yet  has  not  appeared  to  cause  so  much  damage  as  have  the 
species  before  mentioned. 

The  life  history  of  one  of  the  mushroom  maggots  is  about  as  fol- 
lows :  The  eggs,  of  which  each  female  is  capable  of  laying  nearly 
1,000,  are  generally  deposited  at  the  juncture  of  the  stem  and  cap  of 
the  mushroom,  or  in  the  manure  or  soil  at  its  base.  In  a  warm  tem- 
perature they  may  hatch  within  three  days,  but  in  colder  weather  this 
time  may  be  considerably  extended.  Upon  hatching  the  larva?  bore 
at  once  into  the  stem  or  cap  of  the  mushroom,  soon  riddling  the  cap, 
and  causing  the  breaking  down  of  the  mushroom  in  a  short  time. 
On  account  of  the  perishable  nature  of  their  host  they  pass  through 
their  transformations  quickly,  the  larvae  feeding  for  from  7  to  10 
days,  by  which  time  the  entire  cap  is  destroyed.  The  larva1  then 
enter  the  ground,  each  spinning  a  slight  silken  cocoon  just  beneath 
the  surface,  and  pupating.  The  pupa  stage  lasts  from  four  to 
seven  clays,  after  which  the  insects  emerge  as  adults,  soon  afterwards 
pairing  and  ovipositing  for  the  next  generation.  Owing  to  the 
immense  number  of  eggs  deposited  and  to  the  short  life-cycle  the 
rapidity  of  their  increase  is  remarkable,  so  that  the  presence  of  only 
a  few  insects  in  the  mushroom  house  at  the  beginning  of  the  season 
may  result  in  the  presence  of  millions  after  the  beginning  of  warm 
weather,  thus  effectually  preventing  the  cultivation  of  mushrooms. 

CONTROL. 

It  is  evident  that  in  the  control  of  the  mushroom  maggots  measures 
should  be  undertaken  early  in  the  season  for  their  elimination  from 
the  mushroom  house  and  precautions  observed  against  their  subse- 


,    fS    l\  i  i   RIOl   -    i"    Mi   3HROOM8. 


([,i,.iit  entrance.  These  should  begin  with  th<  iction  of  the 
house  or  cellar.  The  building  should  be  so  constructed  as  to  |>< 
of  effective  fumigation  and  should  befitted  with  tighl  screens  of  fine 
wire  gauze,  suitable  to  prevent  tl  i  the  fui  \i  The 
gnats  may  also  be  brought  into  the  house  through  the  agency  of  the 
manure  used  in  the  compost  beds,  so  thai  it  is  well  to  disinfect  or 
sterilize  this  substance  by  means  of  steam.  This  maj  be  accomplished 
by  placing  tin-  manure  or  soil  in  vats  or  boxes,  through  which  -tram 
pipe-,  perforated  to  allow  the  escape  of  the  steam  into  the  boxes,  are 
conducted.  I  See  fig.  2. »  The  manure  should  be  heated  to  a  tern 
lur€  0f  iso  I'.,  which  will  destroy  all  animal  life  occurring  thereii. 
without  injury  to  its  capacity  for  producing  mushrooms.  Fumiga 
Hon  with  bisulphid  of  carbon  just  prei  ious  to  planting  the  mushrooms 
i>  also  productive  of  good  results  in  destroying  maggots  in  the  com- 
post. The  bisulphid  should  Ik-  used  at  a  strength  of  2  to  t  pounds  to 
1,000  cubic  feet  of  ^—  y 


and  should 
be  evaporated  in 
shallow  pans 
placed  in  the 
highest  part  of 
thf  house.  It  is 
wry  inflammable 
ami  even  explosive 
when  brought  into  i 
contact  with  lift* 
or  sparks,  so  that  care  should  be  used  to  avoid  bringing  any  fire 
into  the  building  during  the  process  of  fumigation. 

One  of  the  besl  methods  for  the  destruction  of  the  adults  or  ili<'~ 
in  their  occurrence  in  mushroom  houses  is  fumigation  with  tobacco 
or  nicotine  fumigants  such  as  are  used  in  greenhouses.  I  hese  should 
be  used  in  accordance  with  the  directions  indicated  on  the  package 
for  ■  medium  or  heavy  fumigation.1  Used  in  this  manner,  and  ap- 
plied once  a  week  during  the  bearing  season  of  the  mushroom  bed. 
thi>  method  has  been  so  successful  in  reducing  the  number  of  flies 
that  very  little  damage,  if  any.  resulted  from  the  larva-. 

Fumination  with  pyTethrum  of  dusting  the  powder  over  the  beds 
is  also  effective  against  the  mushroom  maggots  if  taken  in  time,  but 
tobacco  fumigation  mav  be  considered  standard  for  this  use. 


2.      Si  -a  in  in 


,\.  or  rtei  >;i 


[  i  nm- 


« The  proportion  of  nicotine  in  the  several  pi  Dl  «iiat 

odard  dose  lin<  n<  yel   been  formulated. 


INSECTS   INJURIOUS   TO    MUSHROOMS. 


THE  MUSHROOM  MITE. 
(Tyroglyphus  lintneri  Osb.) 

The  mushroom  mite  (Tyroglyphus  lintneri  Osb.)  (fig.  3)  is  a 
minute,  soft-bodied  mite,  smooth  skinned,  and  white  or  whitish  in 
color.  It  is  closely  allied  to  the  common  cheese  mite  (Tyroylyphus 
siro  L.)  and  resembles  that  species  in  appearance.  It  is,  if  anything:, 
more  prolific  than  the  cheese  mite,  becoming  at  times  so  abundant 
in  mushroom  beds  as  to  cover  the  surface  of  the  compost,  and  when 
present  in  such  numbers  is  extremely  destructive,  feeding  upon  the 
mushrooms  in  all  stages  and  penetrating  the  beds  and  destroying  the 

mycelium.  Indeed,  in  one  case 
observet  1  by  Mr.  August  Busck, 
of  this  bureau.1  the  mycelium 
was  destroyed  as  fast  as  it  grew 
from  the  spawn. 

This  species  is  undoubtedly 
the  cause  in  many  cases  of  the 
failure  of  the  spawn  to  grow, 
which  is  likely  to  be  attributed 
to  poor  or  weak  spawn,  or  to 
defective  cultural  conditions. 
The  minute  size  of  the  mites 
causes  their  presence  to  be  little 
suspected,  and  the  failure  of 
the  spawn  to  produce  mycelium 
is  not  understood.  Even  under 
conditions  favorable  to*  the 
growth  of  the  mycelium  it  is 
possible  for  the  mites  to  increase 
to  such  an  extent  that  the  en- 
tire bed  may  be  killed  out. 

Besides  the  injury  to  the  my- 
celium, mushroom  mites  cause 
damage  to  the  fruiting  bodies 
by  eating  into  them,  distorting 
or  destroying  the  young  growth.  In  the  more  mature  mushrooms  the 
mites  may  be  found  clustered  in  groups  consisting  of  individuals  of 
many  sizes,  usually  hidden  in  the  folds  between  the  gills,  where  they 
burrow  into  the  tissue  and  rapidly  break  down  the  cap-. 

No  direct  observations  bearing  on  the  life  history  of  this  species 
have  been  made,  but  judging  from  that  of  related  species  it  is  about 
as  follows:  The  eggs,  which  are  huge  in  proportion  to  the  size  of  the 
mites,  are  laid  in  or  about  the  mycelium  of  the  mushroom,  or  on  the 


PlG.  ". — The  mushroom  mite  (Tiiroijlyphus 
lintneri).  Highly  magnified.  (From 
Banks,  i 


Uiul.  38,  Bar.  Ent.,  V.  ».  Dept  Agr., 


1904. 


i  '    rs    IN. I  l  RI01  a    l<>    Mi  BHBOOM8.  5 

young  or  developing  cap&     Thej  hatch  in  a  Bhort  tim<  into  il bar- 

;n  teristic  six  legged  young,  which  rapidly  mature  to  adults  similar  t<> 
the  one  in  figure  2.  The  time  from  t In-  deposition  of  the  egg  t«»  1 1  * « - 
maturity  of  the  mite  has  not,  to  the  writer's  knowledge,  been  accu- 
rate]} worked  out.  I>ut  undoubtedly  occupies  onlj  a  l'«u  days,  li  is 
on  this  account  that  the  mite  is  able  i<>  increase  bo  rapidly,  apparently 
l*  by  magic,  and  thus  give  rise  to  the  theory  of  spontaneous  genera- 
tion sometimes  advanced  to  explain  this  condition. 

Dnder  certain  conditions  the  hypopus  < >r  migrator)  stage  is  pro- 
duced.  This  stage,  according  to  Banks,1  is  peculiar  i<>  the  family 
Tyroglyphidse,  to  which  this  mite  belongs,  ami  is  quite  remarkable. 
The  mite  develops  a  hard,  chitinous  covering,  has  m>  mouthparts,  and 
i-  provided  with  short  legs  insufficient  for  walking.  On  the  ventral 
sin- face  of  the  body  is  an  area  provided  with  Bucking  disks,  by  means 
of  which  the  hypopus  attaches  itself  to  an  insect  and  is  so  transported 
to  suitable  breeding  grounds  in  other  localities.  On  arrival  at  a  suit- 
able breeding  place  the  mite  detaches  itself  from  its  insect  host,  molts, 
and  soon  becomes  adult.  During  the  hypopus  stage  the  mite  take- 
no  food  and  causes  no  injury  to  the  insect  which  carries  it.  This 
peculiar  stage  is  the  natural  means  t'<>r  the  distribution  of  the  mite  to 
new  localities,  and  is  in  many  cases  responsible  for  it-  appearance  in 
localities  far  from  previously  infested  beds. 

In  addition  to  the  way  mentioned  above,  the  mite  may  obtain 
access  to  mushroom  houses  in  infested  compost  or  in  spawn  from 
infested  houses.  However,  the  greater  part  of  the  infestation  prob- 
ably takes  place  through  the  agency  of  the  small  flies  which  frequent 
mushroom  houses  and  which  carry  the  hypopus  stage  of  the  mite 
from  one  house  to  another. 

R]  Ml  mi  a. 

Little  can  be  recommended  for  the  control  of  the  mushroom  mite 
after  it  has  once  become  established  in  a  house.  Owing  to  the  al>- 
Bence  of  breathing-pores  it  is  little  affected  by  the  fumigants  suitable 
for  the  control  of  the  other  mushroom  pests,  while  applications  of 
sulphur,  tobacco  dust,  and  other  suitable  insecticides  to  the  beds 
Beem  only  to  prove  slightly  inconvenient  to  the  mite.  It  i-  one  of 
the  most  stubborn  pests  with  which  we  have  to  deal  in  mushroom 
culture,  and  may  be  brought  into  the  house  in  almost  any  manure 
that  is  used  for  the  bed.  When  in  the  hypopus  stage  it  is  capable  of 
prolonged  suspension  of  vitality  and  is  likely  to  remain  in  the  house 
for  an  unlimited  time  without  death.  The  only  measures,  there!*, 
that  may  be  considered  are  those  of  prevention. 

When  a  house  becomes  infested,  all  compost  should  be  gathered 
with  the  utmost  care,  remove.]  to  the  outside,  and  thoroughly  disin- 

1  Pro.-.  1".  s.  Nat  Mm.,  wl.  28,  p    7'.'.  1904. 


6  INSECTS   INJURIOUS   TO   MUSHROOMS. 

fected  by  drenching  with  boiling  water,  or  it  may  be  hauled  to  a  dis- 
tance and  spread  upon  the  ground  as  fertilizer,  or  it  may  be  destroyed 
Ivy  burning.  The  ground  occupied  by  the  mushroom  beds  should  be 
thoroughly  scalded,  and  the  woodwork  of  the  mushroom  house  treated 
(o  a  wash  of  creosote  or  crude  carbolic  acid,  either  of  which  is  distaste- 
ful to  the  mites.  After  complete  disinfection  has  been  accomplished 
the  house  should  be  screened,  to  guard  against  subsequent  introduction 
of  the  pest  by  means  of  flics.  All  manure  forming  the  beds  should  be 
steamed,  according  to  the  directions  under  the  head  of  mushroom 
maggots.  Care  should  be  used  to  purchase  spawn  only  from  unin- 
fected houses.  "With  these  precautions  it  is  unlikely  that  trouble  will 
be  experienced  from  the  attacks  of  the  mushroom  mite.  Close  watch 
should  be  kept,  however,  for  any  signs  of  the  presence  of  the  mites 
in  the  beds,  and  the  compost  destroyed  upon  their  first  appearance, 
as  it  is  impossible  to  secure  good  results  with  mushrooms  when  in- 
fested by  these  mites.  All  applications  of  suffi- 
cient strength  to  destroy  the  mites  are  likewise 
injurious  to  the  mushrooms,  and  it  is  futile  to 
attempt  to  control  by  any  artificial  means,  once 
the  mushroom  bed  becomes  infested,  as  the  miles 
are  buried  so  deeply  in  the  compost  that  no  insec- 
ticide will  reach  them. 

A  predaceous  mite  belonging  to  the  Gamasidae 
frequently  occurs  in  beds  infested  by  the  mush- 
room mite,  feeding  upon  the  latter,  and  at  times 
"""".""Vn,      becoming  so  numerous  as  entirely  to  wipe  out  the 

j  u  no  us  springtsul,  =  _  . 

Achoreutea   arm  a-    pest.     The  gamasid  may  be  known  by  its  longer 
turn.    Miicii    en-     j  j  -{    manner  0f  running  swiftly  over  the 

largcd.      (Original.  I  *=  . 

compost  or  the  mushrooms.  The  writer  has  seen 
cases  where  the  gamasid  has  occurred  in  such  abundance  as  greatly 
to  outnumber  its  host.  This  predaceous  enemy  does  not  feed  on  the 
mushrooms  after  the  destruction  of  the  mites,  but  seeks  other  feeding 
grounds,  or  dies  by  starvation. 

SPRINGTAILS. 
{Achoreutes  armatum  Nicolet  et  al.) 

At  times  the  surface  of  a  mushroom  bed  becomes  alive  with  minute 
brown  or  black  insects,  which,  when  disturbed,  leap  about  like  fleas 
in  an  extremely  erratic  manner.  These  are  known  as  springtaiLs, 
since  the  springing  is  performed  by  the  aid  of  two  short  bristles 
situated  on  the  anal  >egment  of  the  abdomen.  These  insects  (Acho- 
reutes  armatum,,  see  fig.  4)  are  present  in  almost  all  manure,  where 
they  feed  on  the  decaying  vegetation  present,  but  on  occasion  they 
may  Income  quite  injurious  in  mushroom  houses.    A  correspondent 


3    IN  i  QRI0U8    i"    M  CT8B  ROOMS.  7 

iii  St.  Louis,  Mo.,  reported  that  in  one  "f  his  mushroom  houses  m  l>cl 
L60  feet  in  length  had  been  completely  destroyed  by  these  pests,  which 
attacked  the  mushrooms  as  fast  a  they  appeared,  honey-combing 
tin-in  and  rendering  them  until  fur  use.  The  method  of  attack 
of  this  insect  is  to  feed  upon  the  fruiting  bodies  of  tin-  mushrooms, 
roying  both  tin-  gills  and  the  cap.  Hundreds  ma\  be  found 
clustered  upon  ;i  single  mushroom  and  eating  large  cavities  in  the 
gills.    Ii  appears  to  he  ;i  habit  <•('  these  insects  t<>  cot  in  large 

numbers  <>n  caps  which  have  been  slightly  injured,  in  which 
they  rapidly  destroy  mushrooms  which  would  be  readily  salable  if 
tin-  injury  were  not  continued.     When  they  occur  in  large  numbers 
they  an-  likely  to  attack  even  the  perfect  mushrooms,  in  aLrLrra\ateil 
cases  destroying  whole  beds. 

Insects  <>f  this  group  pass  through  n<>  larval  transformation,  tin' 
form  of  the  newly  hatched  young  being  similar  to  that  of  the  adult. 
They  are  thus  likely  t<>  be  injurious  in  the  same  manner  throughout 
their  life  history. 

i;i  Mi  nil  S. 

The  remedial  measures  applicable  t"  the  control  of  springtails  are 
i.'   i  large  extent  preventive,  a-  these  insects  are  somewhat  difficult 
ntrol  when  once  established  in  a  mushroom  bed.    They  are  quite 
tan!  to  tobacco  powders,  but  applications  of  buhach  or  pyreth- 
rmn  to  the  beds  are  productive  of  -nine  good.    A-  they  usually  con- 
gregate near  the  surface  of  the  beds  fumigation  with  hydrocy 
acid  gas,  according  to  the  directions  given  in  Circular  -7  of  this 
bureau,  will  prove  effective  in  reducing  their  numbers.    The  cyanid 
should  be  used  at  a  strength  of  from  3  i"  6  ounces  to  each  1,000  cubic 
of  air  space,  which  will  not  prove  injurious  to  the  mycelium. 
By  way  of  prevention,  steaming  all  manure,  a-  previously  sug- 
gested  for  other  species,  will  destroy  springtails  equally  well.    Where 
ble,  it  is  better  to  grow  the  mushrooms  at  a  temperature  of  about 
I".  than  higher,  a-  at   low  temperatures  the  springtails  breed 
much  less  quickly.    Dusting  the  top-  of  the  beds  with  powdered  lime 
is  also  said  to  discourage  attack  by  springfa 

SOWBUGS. 
i  Irmadillidium  spp.  anil  PorceUio  9pp.) 

Considerable  injury  is  often  accomplished  to  mushroom  beds 
through  the  attacks  (>f  oval,  grayish,  or  slate-colored  creature-  bear- 
ing seven  pair-  of  legs.  These  creature-  are  not  true  insects,  although 
known  variously  by  the  term-  "woodlice,"  sowbugs,  and  "pillbugs.'1 
Two  .  the  greenhouse  pillbug   {Armadillidium    vulgan    La- 


8 


INSECTS   INJURIOUS   TO   MUSHROOMS. 


treille)  and  the  dooryard  sowbug  (PorceUio  hi  vis  Koch),  are  illus- 
trated in  figures  5,  6,  and  7. 

Sowbugs  live  in  damp,  dark  places,  such  as  beneath  boards,  in 

cellars,  and  in  the  cracks  of  sidewalks.  When  disturbed  many  spe- 
cies roll  up  to  form  a  ball,  lying  quite  still  until  the  danger  is  past. 
(See  fig.  5.)  During  the  night  they  issue  from 
their  hiding  places  to  feed  upon  decaying  vege- 
table matter,  molds,  and  other  material  present 
in  damp  soils,  although  at  times  the  roots  of 
plants  and  even  the  green  leaves  are  not  es- 
chewed. 

The  young  are  carried  about  in  a  pouch, 
formed  by  several  modified  anal  plates  on  the 
abdomen  of  the  female,  until  able  to  shift  for 
themselves.  "When  released  by  the  female  the 
young  are  similar  in  appearance  to  the  adults, 
although  much  smaller,  and  are  likewise  cap- 
able of  damage.  There 
is  probably  only  one 
generation  annually,  the 
young  making  their  ap- 
pearance in  the  spring  and  requiring  one  sum- 
mer to  reach  maturity. 

The  destruction  occasioned  hj  sowbug-  is 
due  to  their  attacks  on  the  caps  or  fruiting 
bodies  of  the  mushrooms.     These  they  attack 
while  quite  small,  destroying  them  or  injur- 
ing  their   appearance. 
T\\zx  do  not,  as  a  rule, 
attack    the    mycelium, 

but  eat  holes  in  the  young  "  buttons,  which, 
on  the  completion  of  the  growth,  become  much 
larger  and  disfigure  the  product. 

Sowbugs  are,  more  frequently  than  at  first 
might  be  thought,  carried  into  the  mushroom 
house  in  compost  which  has  been  allowed  to 
stand  outside.  The  heat  of  the  manure  is 
relished  by  them,  and  they  collect  in  numbers. 


Fig.  5. — The  greenhouse 
pi  11  bug  (ArmniliUitliina 
vulgare)  extended. 
Much  enlarged.  (Orig- 
inal.) 


Fig.  6. — The  greenhouse 
pillbug  {Armadilliilium 
vulgare)  contracted. 

Much  enlarged.      (Orig- 
inal.) 


Fig.  7. — Dooryard  sowbug 
(Porcellio  Iwvis).  Much 
enlarged.      (Original.) 


remaining  there  throughout  the  growth  of  the 


spawn,  but  becoming  injurious  with  the  first 
growth  of  the  mushrooms.  The  writer  has 
seen  sowbugs  collected  in  manure  piles  to  such  an  extent  that  numbers 
aggregating  a  pint  or  more  in  quantity  might  have  been  collected 
from  a  shovelful  of  material. 


INSECTS    I  n.i  URI01  a    ro    M  I  >il  ROOMS. 

1:1  \u  i. ii  -. 

\\  here  1 1 u>  mushroom  house  i-  small  in  extenl  ii  is  possible  materi- 
ally to  reduce  the  numbers  of  sowbugs  bj  means  of  hand  picking. 
The  house  may  be  visited  at  night,  when,  l>\  the  aid  of  a  lantern, 
Dumbers  of  sowbugs  may  be  seen  crawling  about  on  the  earthen 
casing  of  the  beds  and  upon  the  boards  and  supports  of  the  benches. 
These  may  be  destroyed  with  a  small  wooden  paddle. 

It  is  also  possible  to  secure  good  results  by  pouring  hoi  water  along 
the  cracks  in  the  boards  and  in  other  places  where  the  "bugs"  may 
be  concealed  by  day.  This  is  effective  in  small  establishments,  but  is 
Bomewhat  difficult  <>i'  application  in  large  houses.  In  such  a 
fumigation  with  hydrocyanic-acid  gas  is  an  effective  remedy.  Treat- 
ment with  sulphur  dioxid'  is  also  effective,  but  this  remedy  should 
be  applied  after  the  mushroom  crop  has  been  harvested  and  the  com- 
post  has  been  removed. 

Another  method  i-  to  cut  small  pieces  of  raw  potato,  plastering  the 
wet  surface  with  Paris  green,  and  laying  them  about  on  the  beds  in 
the  localities  affected  by  the  sowbugs.  This  method  is  frequently 
successful  in  entirely  ridding  houses  of  this  pest. 

CRICKETS. 

Among  other  injurious  form-  which  a!  times  attack  mushrooms, 
certain  cricket-  are  reported  as  eating  into  the  caps  of  the  mush- 
rooms, (hi  the  Pacific  coast  a  species  known  scientifically  as  Ceu- 
thophilus  pacificiu  Thorn,  has  been  reported  as  causing  extensive 
injury  to  cultivated  mushroom  beds. 

The  remedies  for  cricket-  in  their  injurious  occurrence  are  the 
same  a>  those  recommended  for  sowbugs  in  a  previous  section  of  this 
circular.  Potatoes  and  carrot-  may  he  minced  before  applying  the 
Paris  green,  in  order  to  secure  a  somewhat  thicker  coat. 

GENERAL   SUMMARY. 

In  the  construction  of  mushroom  houses  care  should  he  taken  to 
make  the  building  a-  tight  a-  possible  and  with  few-  outlets.  If 
window-  are  necessary  they  should  he  -mall  and  should  be  screened 
with  fine  wire  gauze,  which  form-  an  excellent  prevention  against 
the  entrance  of  both  maggots  and  mite-,  a-  previously  mentioned.  If 
possible  all  compost  should  be  steamed  before  being  placed  in  the 
house  and  the  temperature  should  he  kept  below  55  I-".,  as  all  insects 
are  more  or  less  dormant    at   this  temperature,  and  their  otherwise 

reprint    from   BaL  6".   Bur.    KM.,   l      6  Icolrore,   pp.    '  -  ilphtir 

Dioxid  as  an   Insecticide. 


10 


INSECTS   INJURIOUS   TO   MUSIIP.dn  M  B. 


rapid  multiplication  is  thereby  greatly  checked,  reducing  infestation 
to  a  minimum.  If  these  recommendations  are  carefully  followed 
there  should  be  little  necessity  for  the  radical  measures  of  fumigation 

or  destruction  of  the  beds. 

Approved: 

James  Wilson, 

Secretary  of  Agriculture. 
Washington,  D.  C,  April  17,  1912. 


ADDITIONAL  COPIES  of  this  publication 
S\-  may  be  procured  from  the  Superintend- 
ent of  Documents,  Government  Printing 
Office,  Washington,  D.  C. ,  at  5  cents  per  copy 


UNIVERSITY  OF  FLORIDA 


3  1262  09216  5645 


! 


